curse you brush algae.
I have (2) T-5 daylight bulbs that were on about 10hrs a day
i dosed dry micor/marco mix twice a week (
http://www.aquariumfertilizer.com/index.asp)
So i kept the lights off for a week, trimmed off the leaves that had the algae, did a water change.
i have changed to the plant tabs that go in the substrate so that the algae doesn't get to the nutrients.
i have reduced the amount of light to about 6 hours a day. Any other tips to keep it at bay?
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Yes, one more idea on top of what you are doing: floating plants. Water Sprite (
Ceratopteris cornuta) is probably the best, as it is very fast, will grow large (two plants will in not much time completely cover the surface of that tank), provides good shade, and is interesting as a plant. Frogbit is similar. Water Lettuce is another. I would go with these before the tiny plants like Salvinia and Duckweed. Some stem plants do well floating too. Brazilian Pennywort is my favourite for this. Cabomba and Wisteria are two others that should work with your light (they don't for me as I have less intense lighting).
Reducing the photoperiod (duration) is a good move, as you clearly have an imbalance which I will explain. Your T5 lighting I will assume is HO (correct me if this is a mistaken assumption), and that is very bright light. I tried it for a week (two 48-inch tubes over my 5-foot 115g tank) and it was so bright I thought the fish would be asking for sunglasses. [I now have two T8 tubes which works better for me as I have moderate light-requiring plants.] I have not tried the dry fertilizers you linked, since in my situation this would be too much as it would be beyond my light, but from what I have read the dry are a good product. However, one thing missing is carbon. Without CO2 diffusion, the higher light and fertilizers will give algae an advantage, as here. I've been through this too, and I simply reduced my light duration until I found the balance.
This is why I suggest floating plants. Without adding CO2 you are going to have a bit of an imbalance between light and nutrients. But adding the floaters, plus reducing the duration, should help. On the duration I'll just mention that the duration and the intensity are not interchangeable. In other words, if the light is not bright enough, keeping it on longer will not compensate, and vice-versa. Plants need light of a specific intensity (this varies with plant species), balanced by all nutrients being available; only then can they photosynthesize full out. And algae is at a big disadvantage. But as soon as some essential is no longer available, and here it would be CO2 (carbon), photosynthesis will slow and algae has an advantage.
I have been able to eliminate brush algae by reducing the duration of light, and in other cases by lessening the nutrient fertilization. Each aquarium is different biologically, so it can take some experimenting to find that balance.
Increasing CO2 naturally may help too, depending what you are doing maintenance-wise now. CO2 occurs from fish and plant and bacteria respiration, but the majority of CO2 comes from the breakdown of organics primarily in the substrate. Leaving the substrate "dirty," by not cleaning down into it, will keep organics there and provide more CO2. Snails (Malaysian Livebearing, pond, etc) also help as they break down the organic waste faster, allowing the bacteria to get using it quicker.
One comment on substrate vs liquid fertilizers: some nutrients are only taken up primarily via the leaves, so they must be in the water column. You might want to do one liquid dose.
I would leave the light at six hours for the present, and add some floating plants, and perhaps reduce the dry fertilizers. Not knowing their exact composition and quantity in a "dose," I can't say much more on these. Keep a close eye on things. The algae that is there won't go away, but the aim with the changes is to prevent it from increasing, and when that happens, you have found the balance. At that point, you might be able to increase the duration a bit, I would say one hour at a time, leaving it for 3 weeks before any other changes.
Byron.